Communication devices, such as mobile phones and computers, are ubiquitous in today's society. Communication devices are typically used to communicate information between communication device users and use a variety of different applications (e.g., word processing application, email application, social network application, electronic calendar application, alarm clock application, etc.). Certain of these communication devices (e.g., mobile phones, laptop computers) can be powered by battery, which can have limited power supply per charge. To facilitate conserving power, a communication device typically employ a sleep mode wherein the communication device enters a low power consumption mode, typically including partially or completely dimming the display of the device, when no interaction with the communication device is detected for a predetermined period of time.
Also, certain communication devices can have user interfaces (e.g., keyboard, number pad, touch screen, etc.) that can accidentally and undesirably receive input (e.g., keystroke, selection of an application, dialing of a phone number, etc.), for example, when an object (e.g., object in a purse or pocket) or a user's finger accidentally comes into contact with the user interface. To minimize this undesirable interaction with the user interface, many communication devices can be locked so that the user interface is only able to receive certain minimal input, such as input to illuminate the display to the locked screen and/or input to unlock the communication device. One conventional locking/unlocking technique is to have a user slide a lock icon in a horizontal direction from one side of the display to the other side of the display to unlock the communication device. Once unlocked, desired applications can be accessed on the communication device by the user. However, conventional communication-device locking systems still can be accidentally unlocked by accidentally received input (e.g., input that slides (e.g., moves, pushes) the lock icon from the locked to the unlocked position), and/or other undesired input can be accidentally received. It is therefore desirable to provide a security system to minimize the risk of accidentally unlocking the communication device and receiving undesired input via the user interface of the communication device.